The value drops=2 in the gameState controls whether gating in pieces
from the holdings is possible, and implies holdings even if holdings=0.
New incarations of Cardinal and Marshall are added to the piece types,
under the names H and E. Gating has to be entered as promotion ('/' in
stead of '=' is allowed). King does no longer have to be the last piece
type; a macro PIECES has been added to indicate the number of piece types.

Mamer can now 'pause' an indicated tourney, meaning it suppresses starting
a new round. The command 'resume' would then be needed to start the next
round, and reset the pause condition. (Cloned from OpenTourney.)

D and H were not recognized at all, and G was MASTODON. Now D&H are added,
and MASTODON is redefined in parse_move as GOLD when promoType==3.
SAN moves do their own interpretation of the promo suffix, which
was already OK.

This required an extra game parameter to indicate the depth of the
promotion zone. The character 'Z' in the board file sets this to 3. The
promotion code had to be changed to allow for deferral when the last
rank is not yet reached. A missing promo char now defaults to deferral
when possible, and to the highest available piece if not.

The old code would allow any drop, except Pawns on first and last rank,
which is actually too restrictive for Shogi (which does allow back-rank
Pawn drops). Only thing still missing is Pawn drop with mate.

Shogi promotions were implemented by introducing a new promoType
value (3), which can be set y 'S' in the board status line.
Demotion of pieces takes place on capture, by tracing them back with
was_promoted() to their original, which now is not automatically Pawn,
but derived from the piece mentioned in the move string.

Like in Bughouse a promoted Queen is not distinguished from a
primordial one on the board, Golds which are promoted Pawns / Lances /
Knights / Silvers all look the same as a primordial Gold. The Dragon
Horse and Draon King look different from Bishop and Rook, though, and
are indicated by the letters I and J on the board.

The promotion is indicated in the SAN move by suffix =G, =I or =J.
Deferral is not indicated. On input == is understood as deferral, =+ or
=^ (or in fact =<ANY PIECE> as promotion).

The new game types were not everywere mapped on rating types, leading to
a crash. Types KNIGHTMATE, CAPABLANCA and GOTHIC are for the time being
now all treated as WILD, in rating calculations. Eventually these should
all have their own rating type, but this requires an extension of the
rating database format.

In the new logic, the 'category', i.e. the name of the subdirectory of
'data/boards' now should correspond to the variant name used in the
XBoard client. The default setup for the variant is then in the file '0'
inside that, and is used wen no explicit board name is given.